Configuring PWM sysfs entries

[Domenico Andreoli <domenico.andreoli@linux.com>]

Hi,

I'm using fancontrol on a NanoPi M4 having a PWM controlled fan.

This is the configuration I'm using:

INTERVAL=10
FCTEMPS=/sys/class/pwm/pwmchip1/pwm0/duty_cycle=/sys/class/hwmon/hwmon1/temp1_input
MINTEMP=/sys/class/pwm/pwmchip1/pwm0/duty_cycle=45
MAXTEMP=/sys/class/pwm/pwmchip1/pwm0/duty_cycle=70
MINSTART=/sys/class/pwm/pwmchip1/pwm0/duty_cycle=1500000
MINSTOP=/sys/class/pwm/pwmchip1/pwm0/duty_cycle=1500000
MAXPWM=/sys/class/pwm/pwmchip1/pwm0/duty_cycle=10000000

This is effective only after sysfs has been configured:

PWM=0
CHIP=1
POLARITY=normal
PERIOD=10000000

echo $PWM > /sys/class/pwm/pwmchip$CHIP/export
echo $PERIOD > /sys/class/pwm/pwmchip$CHIP/pwm$PWM/period
echo $POLARITY > /sys/class/pwm/pwmchip$CHIP/pwm$PWM/polarity
echo 1 > /sys/class/pwm/pwmchip$CHIP/pwm$PWM/enable

Additional caveat, fancontrol accepts PWM values up to 255 while my
configuration works iff such value is 1500000. Therefore I have to
comment out the max PWM value check in the fancontrol script.

Is this the best way to achieve the result?

Would you accept a patch to improve fancontrol and handle this situation
in a nicer way?

Kind regards,
Domenico

-- 
rsa4096: 3B10 0CA1 8674 ACBA B4FE  FCD2 CE5B CF17 9960 DE13
ed25519: FFB4 0CC3 7F2E 091D F7DA  356E CC79 2832 ED38 CB05